Thermal management materials with high thermal conductivity, high thermal diffusivity, machineability and low coefficient of thermal expansion (“CTE”) at low cost are desirable. For many electronic applications it would be beneficial if the material was not electrically conductive so that electronic components could be assembled directly onto the high thermal conductivity material. However, materials with high thermal conductivity are also typically electrically conductive. For example, carbon-based materials, such as graphite and graphene, typically have high thermal conductivity and are also electrically conductive. It would be desirable to have high thermal conductivity ceramic dielectric layers on graphitic substrates (i.e., a pure graphite substrate or a graphite-metal composite substrate) for fabrication of a high-performance circuit board through printing copper (“Cu”) circuit traces on the top of the ceramic dielectric layers.
Besides providing high thermal performance and sufficient dielectric strength, the dielectric layers should also possess a strong, adhesion with graphitic substrates, be compatible with Cu paste printing and curing processes that require a curing temperature over 400° C., and possess a strong adhesion with the Cu printed circuit traces.